The present invention relates to an internal combustion gasoline engine having an exhaust gas recirculating system therein, and means to provide more trouble-free operation thereof.
Since the early 1960's, large-scale efforts have been undertaken by the automobile industry to control automotive emissions from internal-combustion engines. Initial efforts dealt with the installation of a positive crank case ventilation system (PCV). This system reduces hydrocarbon emissions by circulating fresh air down through the crank case to pick up blowby gases, which are then re-routed through the carburetor and into the combustion chamber, whereupon they will be burned prior to being expelled through the exhaust system.
The next attempt at reducing automotive emissions resulted in the air injection system, wherein oxygen-rich air from the atmosphere is injected into the exhaust manifold of the engine to insure combustion of unburned hydrocarbons before they are expelled as exhaust. Later, a thermostatically controlled air cleaner system was introduced, wherein air entering the conventional air cleaner was heated to raise the combustion temperature of a cold engine, thereby reducing hydrocarbon emissions by improving engine efficiency during warmup of the engine.
The most recent emission system is the exhaust gas recirculation system (EGR). This system is designed to reduce nitrogen oxide emissions by recirculating exhaust gases into the intake manifold to dilute the fuel charge, which thereby reduces peak flame temperature. The EGR's operation has as its main component a vacuum-operated valve, which is designed to emit more and more exhaust gas into the intake manifold as the speed of the engine, and thus the vacuum created thereby, increases. The vacuum sensing line of the EGR is typically connected to the carburetor venturi, and as engine speed is increased, the pressure is lowered at or near the carburetor venturi, which is transmitted to the EGR via the vacuum sensing line. Sensing the lowered pressure, the EGR valve opens, thereby allowing more exhaust gas to be recirculated back through the intake manifold, reducing the ultimate emission of pollutants.
The problems with such a system is that many EGR's recirculate an excessive amount of exhaust gas, thereby causing the automobile to hesitate, surge, and, in some instances, to cease operation, resulting in great fuel waste.
I have now found an uncomplicated device which the average automobile owner can install in the above system to allow for adjustment of the EGR operation such that the automobile will not run poorly.